I-405 to close over the weekend for overpass demolition

For those that didn’t know, going in and picking out a broken girder or two in the middle of the bridge is pretty complicated, expensive and time-consuming. It’s been over a year since a truck hit the Lind Avenue overpass in Renton. This weekend, southbound Interstate 405 will have to close for demolition.

In June 2022, a trailer carrying a backhoe went under the Lind Avenue overpass of southbound I-405. It was too tall.

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“When the backhoe’s arm hit the bridge, it actually hit five of the eight girders,” the Washington Department of Transportation’s Tom Pearce said. “The collision damaged it to the point where it’s just more efficient to replace the entire span than replace the individual girders.”

The solution would have been different if it had hit all the girders.

“It broke some girders, but it didn’t break others,” Pearce said. “It basically broke every other girder, so going in and picking out a broken girder or two in the middle of the bridge is pretty complicated and expensive and time-consuming.”

So, the overpass has to come down. Only the span over southbound I-405 needs to be demolished. This weekend’s closure won’t impact northbound I-405.

“We will need a full closure of southbound I-405 from 11 p.m. Friday, Nov. 3 to 4:30 a.m. Nov. 6 so that we can demolish the old bridge,” Pearce said.

There will also be some nighttime lane closures this week to re-stripe the freeway for the upcoming work. New lane configurations on southbound I-405 through the area will remain until the span is replaced.

“It’ll take about two to three months to rebuild the north span of the overpass, and so we hope to open sometime in early 2024,” Pearce said.

I asked Pearce why it took so long to get to this. He said replacing an overpass isn’t the most straightforward job.

“First, we had to assess the damage and determine the best way to fix the bridge, then we had to create designs, and we had to go out to bid and hire a contractor,” Pearce said.

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The overpass has been open to bikes and pedestrians since the accident, but that won’t be the case in the future. About 16,000 vehicles a day use the Lind Avenue overpass.

Southbound I-405 drivers will be detoured off the freeway at Talbot Road. The detour route will take them down Grady Way and back on the freeway at the West Valley Highway. There will also be some nighttime closures of southbound I-405 next month as the girders are installed.

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